What is a Noxious Weed?

'Noxious weed' is the traditional, legal term for any invasive, non-native plant that threatens agricultural crops, local ecosystems or fish and wildlife habitat. Noxious weeds include non-native grasses, flowering plants, shrubs and trees, and aquatic plants that invade wetlands, rivers, lakes and shorelines. Because of their aggressive growth and lack of natural enemies, these species can be highly destructive, competitive or difficult to control.

Benton County's noxious weed lists are presented in this publication and in the links provided below. Noxious Weeds have been selected from the State Noxious Weed List for control within our county.

There are three categories of noxious weeds, Class A, Class B and Class C. Click the buttons to see images of the weeds in that category that are found in Benton County.


Non-native species whose distribution in Washington is still limited. Preventing new infestations and eradication are the highest priority. Eradication of all Class "A" plants is required by law.

Non-native species presently limited to portions of Washington state. Species are designated for control in regions where they are not yet widespread. Preventing new infestations in these areas is a high priority. 

Are selected by the County Board of Directors. These weeds which are already widespread in Washington state are of special interest to the state's agricultural industry.